diff --git a/.github/workflows/continuous-integration.yaml b/.github/workflows/continuous-integration.yaml
index 3b45526f2..b93a511c8 100644
--- a/.github/workflows/continuous-integration.yaml
+++ b/.github/workflows/continuous-integration.yaml
@@ -227,7 +227,7 @@ jobs:
         os: [ linux ]
         arch: [ x86_64 ]
         network: [ preview ]
-        cardano-node: [ 9.1.0 ]
+        cardano-node: [ 9.1.1 ]
 
     runs-on: ${{ matrix.os == 'linux' && 'ubuntu-22.04' }}
     steps:
@@ -404,8 +404,8 @@ jobs:
         os: [ linux ]
         target: [ cardano-node-ogmios ]
         network: [ mainnet, preprod, preview, sanchonet ]
-        cardano-node: [ 9.1.0 ]
-        cardano-node-latest: [  9.1.0 ]
+        cardano-node: [ 9.1.1 ]
+        cardano-node-latest: [  9.1.1 ]
         arch: [ x86_64 ]
     steps:
     - name: 📥 Checkout repository
diff --git a/.github/workflows/network-synchronization.yaml b/.github/workflows/network-synchronization.yaml
index 197bcb487..77807d3df 100644
--- a/.github/workflows/network-synchronization.yaml
+++ b/.github/workflows/network-synchronization.yaml
@@ -16,8 +16,8 @@ jobs:
     strategy:
       matrix:
         network: [ preview ]
-        ogmios_version: [ v6.6.0 ]
-        cardano_node_version: [ 9.1.0 ]
+        ogmios_version: [ v6.6.2 ]
+        cardano_node_version: [ 9.1.1 ]
 
     runs-on: ubuntu-latest
     steps:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 77cc2e944..8ffe9a3fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,20 @@ pre: "<b>6. </b>"
 math: true
 ---
 
+### [6.7.0] - 2024-09-13
+
+#### Added
+
+- Automatically upgrade transactions from previous era (up until Alonzo) on submission.
+
+#### Changed
+
+- N/A
+
+#### Removed
+
+- N/A
+
 ### [6.6.2] - 2024-09-10
 
 #### Added
diff --git a/Dockerfile b/Dockerfile
index 1667aabd8..e886d415f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,7 +2,7 @@
 #  License, v. 2.0. If a copy of the MPL was not distributed with this
 #  file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-ARG CARDANO_NODE_IMAGE=ghcr.io/intersectmbo/cardano-node:9.0.0
+ARG CARDANO_NODE_IMAGE=ghcr.io/intersectmbo/cardano-node:9.1.1
 
 #                                                                              #
 # --------------------------- BUILD (ogmios) --------------------------------- #
diff --git a/clients/TypeScript/package.json b/clients/TypeScript/package.json
index 21b6fbf2f..ce53bd5d6 100644
--- a/clients/TypeScript/package.json
+++ b/clients/TypeScript/package.json
@@ -1,6 +1,6 @@
 {
   "name": "cardano-ogmios",
-  "version": "6.6.2",
+  "version": "6.7.0",
   "private": true,
   "description": "TypeScript monorepo with client libraries for Cardano Ogmios",
   "engines": {
diff --git a/clients/TypeScript/packages/client/package.json b/clients/TypeScript/packages/client/package.json
index 98069f4fe..436bf64ad 100644
--- a/clients/TypeScript/packages/client/package.json
+++ b/clients/TypeScript/packages/client/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@cardano-ogmios/client",
-  "version": "6.6.2",
+  "version": "6.7.0",
   "description": "TypeScript client library for Cardano Ogmios",
   "engines": {
     "node": ">=14"
@@ -47,7 +47,7 @@
     "typescript": "^4.2.3"
   },
   "dependencies": {
-    "@cardano-ogmios/schema": "6.6.2",
+    "@cardano-ogmios/schema": "6.7.0",
     "@cardanosolutions/json-bigint": "^1.0.1",
     "@types/json-bigint": "^1.0.1",
     "bech32": "^2.0.0",
diff --git a/clients/TypeScript/packages/repl/package.json b/clients/TypeScript/packages/repl/package.json
index 5589a9f4e..061b7cede 100644
--- a/clients/TypeScript/packages/repl/package.json
+++ b/clients/TypeScript/packages/repl/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@cardano-ogmios/repl",
-  "version": "6.6.2",
+  "version": "6.7.0",
   "description": "REPL for Cardano Ogmios",
   "engines": {
     "node": ">=14"
@@ -39,7 +39,7 @@
     "typescript": "^4.2.3"
   },
   "dependencies": {
-    "@cardano-ogmios/client": "6.6.2",
+    "@cardano-ogmios/client": "6.7.0",
     "yargs-parser": "^20.2.7"
   },
   "files": [
diff --git a/clients/TypeScript/packages/schema/package.json b/clients/TypeScript/packages/schema/package.json
index 748d904d2..995c15cc0 100644
--- a/clients/TypeScript/packages/schema/package.json
+++ b/clients/TypeScript/packages/schema/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@cardano-ogmios/schema",
-  "version": "6.6.2",
+  "version": "6.7.0",
   "description": "Generated TypeScript from the Cardano Ogmios schema",
   "engines": {
     "node": ">=14"
diff --git a/docker-compose.yml b/docker-compose.yml
index 8b774d35d..76644d4a0 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -2,7 +2,7 @@ version: "3.5"
 
 services:
   cardano-node:
-    image: ghcr.io/intersectmbo/cardano-node:9.1.0
+    image: ghcr.io/intersectmbo/cardano-node:9.1.1
     command: [
       "run",
       "--config", "/config/config.json",
diff --git a/docs/content/api/_index.md b/docs/content/api/_index.md
index ec5937d6b..608eb90ce 100644
--- a/docs/content/api/_index.md
+++ b/docs/content/api/_index.md
@@ -1,5 +1,5 @@
 +++
-title = "WebSocket API Reference (v6.6.*)"
+title = "WebSocket API Reference (v6.7.*)"
 weight = 4
 chapter = false
 pre = "<b>4. </b>"
diff --git a/docs/static/api/specification.yaml b/docs/static/api/specification.yaml
index ca543fdf0..722ee4efb 100644
--- a/docs/static/api/specification.yaml
+++ b/docs/static/api/specification.yaml
@@ -1,7 +1,7 @@
 asyncapi: '2.4.0'
 info:
   title: Ogmios
-  version: '6.6.*'
+  version: '6.7.*'
   description: |
 
     ### Protocols
diff --git a/server/src/Ogmios/App/Protocol/TxSubmission.hs b/server/src/Ogmios/App/Protocol/TxSubmission.hs
index aa33ed62f..1bbdae030 100644
--- a/server/src/Ogmios/App/Protocol/TxSubmission.hs
+++ b/server/src/Ogmios/App/Protocol/TxSubmission.hs
@@ -53,6 +53,7 @@ import Cardano.Ledger.BaseTypes
 import Cardano.Ledger.Core
     ( EraTx (..)
     , EraTxBody (..)
+    , eraName
     )
 import Control.Monad.Trans.Except
     ( Except
@@ -85,8 +86,10 @@ import Ogmios.Control.MonadSTM
     , takeTMVar
     )
 import Ogmios.Data.EraTranslation
-    ( MultiEraUTxO (..)
+    ( MostRecentEra
+    , MultiEraUTxO (..)
     , Upgrade (..)
+    , upgradeGenTx
     )
 import Ogmios.Data.Json
     ( Json
@@ -128,10 +131,14 @@ import Ouroboros.Consensus.Cardano.Block
     , CardanoBlock
     , CardanoQueryResult
     , GenTx (..)
+    , HardForkApplyTxErr (..)
     )
 import Ouroboros.Consensus.HardFork.Combinator
     ( HardForkBlock
     )
+import Ouroboros.Consensus.HardFork.Combinator.AcrossEras
+    ( EraMismatch (..)
+    )
 import Ouroboros.Consensus.HardFork.Combinator.Ledger.Query
     ( QueryHardFork (..)
     )
@@ -180,6 +187,7 @@ import Type.Reflection
 import qualified Codec.Json.Rpc as Rpc
 import qualified Data.Aeson as Json
 import qualified Data.Map.Strict as Map
+import qualified Data.Text as T
 import qualified Ouroboros.Consensus.HardFork.Combinator as HF
 import qualified Ouroboros.Consensus.Ledger.Query as Ledger
 import qualified Ouroboros.Network.Protocol.LocalStateQuery.Client as LSQ
@@ -212,6 +220,16 @@ mkTxSubmissionClient tr defaultWithInternalError TxSubmissionCodecs{..} Executio
     await :: m (TxSubmissionMessage block)
     await = atomically (readTQueue queue)
 
+    isMostRecentEra era =
+        T.toLower (toText era) == T.toLower (toText (eraName @(MostRecentEra block)))
+
+    -- NOTE: On successful submission, clear our cached
+    -- mempool to ensure we always use the latest available
+    -- mempool snapshot during evaluation.
+    clearMempoolOnSuccess = \case
+        SubmitSuccess -> clearMempoolM
+        _ -> pure ()
+
     clientStIdle
         :: m (LocalTxClientStIdle (SerializedTransaction block) (SubmitTransactionError block) m ())
     clientStIdle = await >>= \case
@@ -219,17 +237,34 @@ mkTxSubmissionClient tr defaultWithInternalError TxSubmissionCodecs{..} Executio
             defaultWithInternalError clientStIdle yield toResponse $ case request of
                 MultiEraDecoderSuccess transaction -> do
                     pure $ SendMsgSubmitTx transaction $ \result -> do
-                        -- NOTE: On successful submission, clear our cached
-                        -- mempool to ensure we always use the latest available
-                        -- mempool snapshot during evaluation.
                         case result of
-                            SubmitSuccess -> clearMempoolM
-                            SubmitFail{} -> pure ()
-                        mkSubmitTransactionResponse transaction result
-                            & toResponse
-                            & encodeSubmitTransactionResponse
-                            & yield
-                        clientStIdle
+                            SubmitFail (ApplyTxErrWrongEra eraMismatch) | isMostRecentEra (ledgerEraName eraMismatch) -> do
+                                case upgradeGenTx transaction of
+                                    Left hint -> do
+                                        SubmitTransactionFailedToUpgrade hint
+                                            & toResponse
+                                            & encodeSubmitTransactionResponse
+                                            & yield
+                                        clientStIdle
+                                    Right upgradedTx ->
+                                        pure $ SendMsgSubmitTx upgradedTx $ \result' -> do
+                                            clearMempoolOnSuccess result'
+                                            mkSubmitTransactionResponse transaction result'
+                                                & toResponse
+                                                & encodeSubmitTransactionResponse
+                                                & yield
+                                            clientStIdle
+                            _ -> do
+                                -- NOTE: On successful submission, clear our cached
+                                -- mempool to ensure we always use the latest available
+                                -- mempool snapshot during evaluation.
+                                clearMempoolOnSuccess result
+                                mkSubmitTransactionResponse transaction result
+                                    & toResponse
+                                    & encodeSubmitTransactionResponse
+                                    & yield
+                                clientStIdle
+
                 MultiEraDecoderErrors errs -> do
                     SubmitTransactionDeserialisationFailure errs
                         & toResponse
diff --git a/server/src/Ogmios/Data/EraTranslation.hs b/server/src/Ogmios/Data/EraTranslation.hs
index 1af9e44fd..fafa1afa1 100644
--- a/server/src/Ogmios/Data/EraTranslation.hs
+++ b/server/src/Ogmios/Data/EraTranslation.hs
@@ -16,6 +16,7 @@ module Ogmios.Data.EraTranslation
 
       -- * Translations
     , Upgrade (..)
+    , upgradeGenTx
     ) where
 
 import Ogmios.Prelude
@@ -51,13 +52,20 @@ import Data.Maybe.Strict
 import Ouroboros.Consensus.Cardano
     ( CardanoBlock
     )
+import Ouroboros.Consensus.Cardano.Block
+    ( GenTx (..)
+    )
 import Ouroboros.Consensus.Shelley.Ledger
     ( ShelleyBlock
     )
+import Ouroboros.Consensus.Shelley.Ledger.Mempool
+    ( GenTx (..)
+    )
 
 import qualified Cardano.Ledger.Alonzo.Tx as Alonzo
 import qualified Cardano.Ledger.Babbage.TxBody as Babbage
 import qualified Cardano.Ledger.Conway.Core as Conway
+import qualified Cardano.Ledger.Core as Core
 import qualified Cardano.Ledger.Crypto as Ledger
 
 type family MostRecentEra block :: Type where
@@ -106,6 +114,35 @@ instance
             let isValid = Alonzo.isValid tx
             pure $ AlonzoTx{body,wits,auxiliaryData,isValid}
 
+----------
+-- GenTx
+----------
+
+upgradeGenTx
+    :: forall crypto.
+        ( Crypto crypto
+        )
+    => GenTx (CardanoBlock crypto)
+    -> Either Text (GenTx (CardanoBlock crypto))
+upgradeGenTx = \case
+    GenTxByron _ ->
+        Left "cannot upgrade from Byron transaction: too old, use a more recent transaction builder."
+    GenTxShelley _ ->
+        Left "cannot upgrade from Shelley transaction: too old, use a more recent transaction builder."
+    GenTxAllegra _ ->
+        Left "cannot upgrade from Allegra transaction: too old, use a more recent transaction builder."
+    GenTxMary _ ->
+        Left "cannot upgrade from Mary transaction: too old, use a more recent transaction builder."
+    GenTxAlonzo (ShelleyTx hash txInAlonzo) -> do
+        txInBabbage <- left show $ Core.upgradeTx @(BabbageEra crypto) txInAlonzo
+        txInConway  <- left show $ Core.upgradeTx @(ConwayEra crypto) txInBabbage
+        pure $ GenTxConway $ ShelleyTx hash txInConway
+    GenTxBabbage (ShelleyTx hash txInBabbage) -> do
+        txInConway <- left show $ Core.upgradeTx @(ConwayEra crypto) txInBabbage
+        pure $ GenTxConway $ ShelleyTx hash txInConway
+    latest@(GenTxConway(_))->
+        Right latest
+
 unsafeFromRight :: (HasCallStack) => Either Text a -> a
 unsafeFromRight = either error id
 
diff --git a/server/src/Ogmios/Data/Protocol/TxSubmission.hs b/server/src/Ogmios/Data/Protocol/TxSubmission.hs
index 33b36b211..75b8dee26 100644
--- a/server/src/Ogmios/Data/Protocol/TxSubmission.hs
+++ b/server/src/Ogmios/Data/Protocol/TxSubmission.hs
@@ -254,6 +254,7 @@ _decodeSubmitTransaction =
 data SubmitTransactionResponse block
     = SubmitTransactionSuccess (GenTxId block)
     | SubmitTransactionFailure (SubmitTransactionError block)
+    | SubmitTransactionFailedToUpgrade Text
     | SubmitTransactionDeserialisationFailure [(SomeShelleyEra, Binary.DecoderError, Word)]
     deriving (Generic)
 deriving instance
@@ -281,6 +282,16 @@ _encodeSubmitTransactionResponse _proxy
             resolve $ encodeObject ("transaction" .= encodeTransactionId i)
         SubmitTransactionFailure e ->
             encodeSubmitTransactionError reject e
+        SubmitTransactionFailedToUpgrade hint ->
+            reject Rpc.FaultInvalidParams
+                "Non-upgradable transaction; it seems that you're trying to submit a \
+                \transaction in a format that presents incompatibility with the current \
+                \ledger era. The field \"data.hint\" contains possible useful information \
+                \about what went wrong."
+                (pure $ encodeObject
+                    ( "hint" .= encodeText hint
+                    )
+                )
         SubmitTransactionDeserialisationFailure errs ->
             encodeDeserialisationFailure reject errs